Which of the following could be added to 1.0 liter of 0.10 M HC2H3O2 (Ka = 1.8 x 10^-5) to form a buffer solution with pH between 4 and 5?
1. 0.050 mol HCI
II 0.050 mol NaOH
III. 0.050 mol NaC2H:02
a. I only
b. II only
c. I and II only
d. II and III only
e. I and III only

it should be p1 v1 = p2 v2

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

i think tornado but not 100%